SlashGear reports that AT&T will enable HD Voice for the iPhone 5 later in 2013, slamming T-Mobile USA’s exclusive on the high-quality voice call system in the process.

News that AT&T is to hop on board the HD Voice train is likely to come as a disappointment to T-Mobile USA, which cited the technology as one of its differentiators after confirming it was finally going to offer the iPhone 5 from early April.